銣87原子的二維磁光陷阱之設計及架設

A two-dimensional magneto-optic trap for Rb-87 atoms

陳保鋼(Pao-Kang Chen)

指導教授 ： 褚志崧

國立清華大學/理學院/物理學系/碩士(2015年)

https://doi.org/10.6843/NTHU.2015.00240

摘要

磁光陷阱(magneto-optical trap, MOT)在實驗物理中是一個相當廣泛且實用的技術，在量子光學領域中，在MOT中以原子氣體非線性光學spontaneous four wave mixing (SFWM)方式來產生糾纏光子，或者做為光儲存，都是相當重要的應用。
傳統的3D MOT是使用一對anti-helmholtz線圈，在空間中的三個維度製造出磁場梯度，將原子團集中在線圈中心點附近，而成為球型原子團。我們使用兩對anti-helmholtz線圈，在空間中只有兩個維度有磁場梯度，使得原子團被集中在一個軸的附近，而成為雪茄型的原子團，由於原子團變長了，其optical density (OD)也隨著提升，另外一個好處是原子團軸上沒有磁場。
我們建立的Rb87 2D MOT計畫在未來有兩個應用，其一是藉由spontaneous four wave mixing (SFWM)方式來產生糾纏光子，計畫將單光子儲存在另一冷銣原子系統中，可以做光子儲存相關的實驗。其二是此系統也可以做為光儲存系統。此篇論文將會著重於如何架構出如此系統的細節。

關鍵字

磁光陷阱 ； 二維 ； 四波混頻 ； 銣87

並列摘要

Magneto-optical trap (MOT) is a practical technique widely used in experimental physics. In quantum optics, atomic gas in a MOT have important applications such as entangled-photon generation (by spontaneous four-wave mixing, SFWM) or photon storage.
Conventional 3D MOT uses one pair of anti-Helmholtz coils to create a gradient in three dimensions so as to confine the atoms around the center and form a spherical cloud. In contrast, we use two pairs of anti-Helmholtz coils to create gradient in two dimensions and realize a 2D MOT. The atoms are confined along one axis and form a cigar-shape cloud. Compared to a 3D MOT, the optical density (OD) increases due to longer cloud and the gradient is zero along the long axis.
Our 2D MOT for Rb-87 atoms has two potential applications: (1) entangled photon pair can be generated using SFWM and one photon in the pair will be stored in another MOT of Rb atoms for studying photon storage, and (2) the atoms in the MOT can be used to store incident photons. This thesis will focus on the details of the construction of the 2D MOT.

並列關鍵字

MOT ； 2D ； FWM ； Rb87

參考文獻

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